Rubber sheeting materials are used in a variety of applications, e.g. tank lining, pond liners, roofing membranes,etc. When the area to be covered is greater than the width or length of the rubber sheets, it becomes necessary to lap splice two or more sheets together. As a practical matter, it is desirable that these splices be made as quickly as possible without undue preparation of the mating surfaces. Furthermore, it is desirable to avoid the presence of foreign substances or contamination which may effect the integrity of the splice.
Typical manufacturing processes for rubber sheets, such as is disclosed in U.S. Pat. No 4,343,667, use dusting compounds applied to each side of the uncured sheets prior to storing in roll form on a curing mandrel in order to prevent the sheeting material from sticking to itself. The particles of dusting powder become embedded into the surface of the rubber sheet during the rolling-up and curing cycles, necessitating their removal prior to splicing. One commonly used method for cleaning the splice area has been to wash the area with solvents using brushes or rags. This method is time-consuming and requires great care to avoid any detrimental effects on the environment due to the use of volatile solvents.
The need for rubber sheeting having clean splice edges, particularly as applied to EPDM roofing membranes, has been described by S. A. Westley and E. L. Polaski in a paper presented at the Akron Rubber Group Winter Symposium, Jan. 26, 1984, and published in Elastomerics magazine, May 1984. p. 13.